During the past several years we have continued our research efforts to achieve an understanding of the complex organization of the seminiferous epithelium, in particular, the structure-function relationship of Sertoli and germ cells. We plan to continue this interest emphasizing the interdependence of Sertoli and germ cells. Androgen binding protein (ABP) is produced by Sertoli cells under hormonal control, but little is known about its role in sperm maturation. We have obtained highly specific antiserum to ABP and a major objective of our work in the next three years will be to use the peroxidase-antiperoxidase (PAP) immunocytochemical method, at the light and electron microscopic level, to localize ABP in testis and epididymis. The importance of structural proteins, such as actin, myosin and tubulin, in various metabolic cell functions is gradually emerging. A second major emphasis of our research is to determine the role of the Sertoli cell structural proteins in spermatogenesis. Using the PAP immunocytochemical technique we plan to localize actin, myosin and tubulin in normal and experimental rats. Another aspect of our work concerns studies in primates. We propose to examine the reproductive system of an ape- the baboon (Papio anubis) using light and electron microscopy. We hve also obtained human testicular biopsies from adults and children exhibiting a wide range of disorders. Our aim in this part of the work is to attempt to correlate the structure of the testis with the hormone data and the pathological condition of the patient. Investigators in the Republic of China have shown that gossypol acts as a male contraceptive. We wish to carry out experiments with gossypol in rats to determine its mechanism of action.